Free volume change in crystallization process of Zr–Cu–Al metallic glass studied by positron annihilation techniques
Free volume change in crystallization process of Zr–Cu–Al metallic glass studied by positron annihilation techniques
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正电子湮没技术研究Zr-Cu-Al金属玻璃结晶过程中的自由体积变化
DOI：
10.1016/j.jallcom.2006.08.143
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发表时间：
2007
影响因子：
6.2
通讯作者：
T. Konno
中科院分区：
文献类型：
--
作者：
F. Hori;T. Yano;Y. Yokoyama;Y. Akeno;T. Konno
正电子湮没寿命（PAL）和重合多普勒展宽（CDB）实验已被用来研究Zr-Cu-Al块体金属玻璃中的自由体积变化和原子弛豫行为。 Zr50Cu40Al10金属玻璃在673K下等温退火，该温度低于玻璃化转变温度(Tg)。在此退火过程中，观察到 PAL 减少，表明自由体积减少；然而，CDB 光谱没有检测到显着变化。这一观察结果表明，低于 Tg 的弛豫发生时原子构型没有变化。对于在 723K (>Tg) 退火 100 秒并随后在 673K 等温退火 18,000 秒的样品，PAL 也类似地下降，表明自由体积减少。此外，CDB谱显示出电子动量分布的系统波动，特别是在高动量区域。这表明在结晶过程中发生了化学重排。
Positron annihilation lifetime (PAL) and coincidence Doppler broadening (CDB) experiments have been performed to study free volume changes and atomic relaxation behavior in Zr–Cu–Al bulk metallic glass. Zr50Cu40Al10metallic glass was annealed isothermally at 673K, which is below the glass transition temperature (Tg). During this annealing, PAL was observed to decrease, indicating a decrease in free volume; whereas, no significant change in CDB spectra was detected. This observation implies that the relaxation below Tgtakes place without a change in atomic configuration. As for specimens annealed at 723K (>Tg) for 100s and subsequently annealed isothermally at 673K for 18,000s, PAL decreased similarly, suggesting a decrease in free volume. In addition, CDB spectra showed a systematic fluctuation of electron momentum distribution, especially in a high momentum region. This indicates that a chemical reordering took place during crystallization process.